The Herald is seeking further comment from the police, Commissioner Andrew Coster and Police Minister Poto Williams about this situation.
The inspector in question has also been contacted for comment.
He may face charges as a result of the alleged breach.
It was revealed last night that the man crossed the border earlier this month - while Auckland was still under stringent Covid-19 alert level restrictions and formal exemptions were needed to leave the area.
One source said the officer was challenged by police staff manning the southern border - but they reportedly allowed him through after he insisted they couldn't say no to him.
He told them that he could cross the border because he was an essential worker.
However it is understood the trip was not considered official police business and police have confirmed no exemption was given for travel.
Last night police wouldn't confirm specific details of the alleged breach.
The Independent Police Conduct Authority has been notified and fellow officers are now investigating the border breach allegations.
A Tamaki Makaurau police spokesperson was able to confirm an internal investigation was under way into the alleged border breach.
That investigation was into "an alleged police decision to allow travel through a boundary checkpoint without an appropriate exemption".
"As police currently understand it, this involved a member of police accompanying a group of people across an alert level boundary so they could attend a burial a short distance away," said the spokesperson.
"Police have confirmed the travel was not permitted ... but further inquiries into the matter are required to more fully understand the context, including decision-making around the case."
Auckland has been in alert levels 3 and 4 - which carry strict travel restrictions - since it was announced in August that the highly infectious Delta variant of Covid-19 was present in the community.
More than 320,000 vehicles have been stopped at checkpoints on the city's southern and northern boundaries in that time, police noted this evening in the organisation's daily compliance update.
Of those, 5524 have been turned around.
Police have also noted over the past month multiple arrests for people crossing the border in breach of lockdown rules - the most notable being a couple accused of using their essential worker exemptions to drive to Hamilton before taking a flight to a holiday home in Wānaka.
In that case one of the alleged offenders was the son of an Auckland District Court judge.
"It's important to remember that travel across an alert level boundary remains restricted and you will be turned away if you don't have the required evidence for permitted travel, as outlined on the Covid-19 website," a police spokesperson said yesterday.
Other high-profile breach cases have included:
• A 53-year-old arrested at Wellington's ferry terminal after police said he crossed Cook Strait with a caravan he'd bought in Christchurch, after misusing work exemption to leave Auckland.
• A woman, 24, and man, 41, arrested in Wellington after allegedly travelling from Auckland.
• Two Aucklanders accused of using false documents to visit Taupō.
• Three essential workers from Auckland allegedly caught at Mt Ruapehu's Turoa Ski Field.
• A man who boasted on Tik Tok of making a cross-border McDonald's run.
• Two gang associates accused of trying to flee police on a gravel road near the lockdown border. The pair were later found to have over $100,000 in cash in the car and a boot full of KFC, police said.
